The prior art reveals several patents relating to tow vehicles of the type use for maneuvering aircraft into and out of hangers or otherwise on the ground. Among those patents considered to be representative of the present invention are U.S. Pat. No. 3,025,922 to Savidge; U.S. Pat. No. 3,038,550 to Lehmann et al; and U.S. Pat. No. 3,662,911 to Harman. The tow vehicles disclosed in the Savidge and Lehmann patents are both gasoline powdered and both are of the type which engage the axle of the aircraft nose wheel to connect the vehicle thereto for moving the craft over the ground. The Savidge vehicle is designed to move small and medium size aircraft but is still of rather large and complicated structure. A friction drive means is provided by Savidge which actually engages the nose wheel of the aircraft in order to move the craft, therefore making it extremely difficult to maneuver and control manually if necessary. The Lehmann vehicle is used for moving jet fighter planes from hangers and parking areas to the ready line. As mentioned before the Lehmann vehicle is gasoline powered and is of a design which secures the nose wheel of the aircraft in order to move it. Consequently, Lehmann's vehicle and others like it are of much heavier structure and are thereby more difficult to maneuver and probably expensive for small private fixed base operations.
Of the patents cited above the Harman U.S. Pat. No. 3,662,911 is the only small, electrically operated tow vehicle. Harman discloses that the batteries may be omitted and the D.C. motor driven by an electrical connection to the aircraft battery or to the aircraft ground power supply. The D.C. motor is connected to a sprocket on the axle of the tow vehicle and thus operates at one speed only. Unless this speed is very slow, maneuverability is limited. Further, the Harman vehicle cannot be freewheeling. As an added disadvantage the Harman device, as do many others in the prior art, uses a scoop or platform to support the nose wheel of the aircraft while the craft is being towed, rather than direct towing. There is no disclosed difference in speed in towing forwardly or in reverse.